1893.] -^^1 |Uaur. 



2. I. gangetica Cuv. 



Locality of type, Ganges. 



3. /. hurum Gray, 1837. 



Locality of type, Ganges (probably). 



Chitra Gray, 1844. 



1. Type, Tnonyx indicus Gr-Aj, 1831. 



Locality of type, Ganges, Pinang. 



Pelochelys Gray, 18G4. 



1. Type, Pelochelys cantorii Gray, 1864. 



Locality of type, Pinang. 



2. P. cummingii Gray, 1864. 



Locality of type, Philippines. 



3. P. poljakowii, Strauch. 



Locality of type, Fu-tschau. 



It may be seen that in the circumscription of the species I have nearly 

 completely followed Boulenger. This, however, is only provisionary. I 

 am fully convinced that Boulenger has gone too far in contracting species. 

 This I may especially say in regard to h's Trionyx sinensis, triungiiis and 

 subplanus. Further detailed studies have to decide about this question. 



I do not believe at all that the system proposed here is finished ; but I 

 think that it gives a more correct idea of this diflRnult group of tortoises. 

 Much remains to be done yet for an exact knowledge of the Asiatic and 

 African forms. But it is only by an exhaustive study of the osteological 

 characters that any light can be brought here. 



January 15, 1892. 



IV. The Species op the Genus Pseudemys. 



The genus Pseudemys was established by Gray* in 1855. The species 

 referred to it were I'estudo concinna LeC, Emys hieroglypliica Holbr. 

 {Pseudemys (?) Meroglypldea Gray) and Testudo rmbiventris LeC. (Pseu- 

 demys serrata Gray). Two years later, Agassiz \ gave the generic name 

 Ptychemys to the same group, distinguishing the following species : 

 Ptychemys rugosa Ag. (Testudo ruiiventris LeC). 

 " concinna Ag. 



" mobiliensis Ag. 

 " JiieroglypMca Ag. 



" decussata Ag. 

 It is evident that Ptychemys Ag. is a synonym of Pseudemys Gray. As 

 the type of this genus I consider Testudo concinna LeC. 



*Gray, J. E., Calal. Shield Rept. Coll. Brit. Mas., Part i, " Testudinata," London, 185.5. 

 t Agassiz, Louis, Contrib.Nat Hist. Vn. States, VoL i, Boston, 1857. 



